Sitting down to binge-watch more than four hours of TV a day could increase a man’s risk of developing bowel cancer, a new study has suggested.
Compared to those who watched one hour or less per day, watching more than four hours of TV was associated with a 35% greater risk of developing bowel cancer in men. The results were not the same for women.
Interestingly, researchers found no link between computer screen time and bowel cancer risk.
Dr Neil Murphy, lead researcher based at the International Agency for Research on Cancer (IARC) in France, said: “Previous research suggests that watching TV may be associated with other behaviours, such as smoking, drinking and snacking more, and we know that these things can increase the risk of bowel cancer.
“Being sedentary is also associated with weight gain and greater body fat. Excess body fat may influence the blood levels of hormones and other chemicals which affect the way our cells grow, and can increase bowel cancer risk.”
It is one of the largest studies to date investigating the link between sedentary behaviour and bowel cancer risk. Researchers analysed data from more than 500,000 men and women for the study, which was published in the British Journal of Cancer.
After six years of follow-up, 2,391 people from the UK Biobank study went on to develop bowel cancer.
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When researchers from the IARC, Imperial College London and the University of Oxford analysed the data, they made the link between sedentary behaviour and bowel cancer. Perhaps unsurprisingly they also found an increase in physical activity was associated with lower bowel cancer risk in men.
The disease is the third most commonly diagnosed cancer in UK men. There were around 41,800 newly diagnosed cases of bowel cancer in men and women in 2015.
Professor Linda Bauld, Cancer Research UK’s prevention expert, said: “This study poses interesting questions such as why screen time from computers didn’t increase the risk of bowel cancer but watching TV did. There is evidence that greater exposure to TV junk food adverts increases the likelihood of eating more, which will also increase your chances of becoming overweight.
“It’s interesting that only men who watched a lot of TV had an increased risk of bowel cancer, but not women. The study didn’t look at this directly, but it could be because men might smoke, drink and eat more unhealthily than women while watching TV.
“We’ll need further research to answer the questions this study raises. What we do know is that keeping a healthy weight, cutting back on alcohol, being physically active and eating a diet rich in fruit and vegetables are known to cut your risk of bowel cancer.”